It is most important to prevent infection or disease in chicken farms. The utilization of drinking devices has generally been successful in the prevention of infection or disease.
Drinking devices should be designed to be leakproof, economic to manufacture, have utility, and not be subject to blockage at a low flow rate of water.
In actual practice, the above-mentioned properties are difficult to realize because scale, which is readily formed by the ions of calcium and magnesium in water, causes drinking devices to be leaky and blocked. For example, the mammillary drinking devices made by American VL Company, or made in Shanghai, both of which are available in China and which have excellent reputations, cannot achieve automatic descaling. Even if scale is not accumulated in these drinking devices, water is leaked from both devices at a rate of approximately one drop every fifteen minutes.
Furthermore, the volume of the water supply cannot be adjusted on the existing drinking devices. Such designs fail to take into consideration and compensate for the unbalanced volume of water supply, which is due to the length of the water pipe and the difference in pressure between the pipe ends.
Soviet Patent SU1586642 and European Patent EP69081 have respectively disclosed drinking devices with flowrate autocontrolling. The device disclosed in EP69081 comprises a pump, a tank and a flexible siphon pipe. The device disclosed in SU1586642 is equipped with a magnetoelectric device and includes a water supplying pipe, a floating rod and a magnet coupled with a magnet plate, etc. Such devices are complicated in structure, but do not avoid scale accumulation in the drinking devices, which results in leakage and eventual blockage.
U.S. Pat. No. 4,896,629 discloses a watering device for poultry comprising a casing, a valve assembly including a valve seat and a valve stem end connecting with a main water pipe, and a sealing member. The end of the valve stem may be pecked by the poultry so as to open the valve, and an elastic element in the valve assembly causes the valve stem and the sealing member to return to a closing position. However, such a valve is also deficient, in that scale is readily accumulated on the valve seat and the seal member, which produces the same problems of leakage and blocking as is encountered by other prior art devices.
Finally, all of the known prior art devices are mounted vertically. Consequently, some drops of water may not enter the chicken's mouth, but will drop to the floor or to the ground when the drinking device is operated.